This invention relates to processes for the manufacture of cationic polyurethane compositions and quaternary ammonium salts and to the new compositions prepared thereby. In particular this invention relates to the use of alkylene oxides to prepare cationic polyurethane compositions and quaternary ammonium salt intermediates. An important aspect of the present invention is the use of alkylene oxides such as ethylene oxide and propylene oxide to form cationic ammonium moieties in polyurethanes.
It has been known for some time that water dispersible polyurethane compositions can be prepared and used to form films. Various procedures have been disclosed in the literature for making polyurethanes water soluble without diminishing the film forming capabilities of the polyurethanes.
U.S. Pat. No. 3,470,310 (Dietrich et al.) describes the preparation of water dispersions of polyurethanes which contain salt type groups bonded into the polyurethane.
U.S. Pat. No. 3,873,484 (Bluestein et al.) discloses aqueous dispersions of polyurethanes prepared from a quaternized polyurethane prepolymer prepared by reacting from 0.6 to 1.2 equivalents of an alkoxylated diol; one hydroxyl equivalent of an N-alkyl dialkanolamine; about 4 equivalents of an organic diisocyanate and quaternizing with 0.5 equivalents of a dialkyl sulfate quaternizing agent. This quaternized polyetherurethane is chain extended to form a polyurethane-urea and dispersed in water in the presence of a nonionic surfactant belonging to the class of alkoxylated long chain alkyl phenols having an HLB of between about 14 and 16.
The use of dialkyl sulfates, such as dimethyl sulfate, and alkyl halides, such as chloroacetoamide, to quaternize tertiary nitrogen atoms is well known. These compositions, however, possess undesirable characteristics limiting their use in the preparation of cationic polyurethanes.
Dimethyl sulfate, an often used dialkyl sulfate, is highly toxic and difficult to use on a large scale. Alkyl halides such as chloroacetamide are corrosive and require the use of expensive equipment, such as special types of stainless steel.
Therefore a general object of the present invention is to provide a method of preparing cationic polyurethane compositions.
Another object of the present invention is to provide a method of preparing quaternary ammonium salt intermediates.
Another object of the present invention is to provide a process for the preparation of quaternary amines containing reactive hydroxyl groups by a method that avoids the use of corrosive or toxic reactants.
Another object of the present invention is to provide new quaternized polyurethane compositions.
Another object of the present invention is to provide water dispersible polyurethane polymers.
Another object of the present invention is to provide polyurethane compositions that form stable films.
Other objects of the present invention will become apparent from the ensuing description.